The present invention relates to an apparatus for separating conical tubes individually one-by-one from a plurality of conical tubes nested axially with respect to one another, utilizing respective gripping mechanisms for grippingly engaging the last-nested and penultimate ones of the nested arrangement of tubes. The gripping mechanisms of the present invention are arranged for relative rotation opposite one another for loosening the last-nested and penultimate tubes and for relative axial shifting to axially separate such tubes.
As is well known, conical tubes, such as utilized for yarn winding in the textile industry, may be compactly stored in nested relation to one another, i.e. with the smaller diameter end of one conical tube inserted into the larger diameter end of another conical tube. A plurality of conical tubes nested in this manner thus form a stack or column from which individual tubes must be separated for use at a textile machine or the like, typically by drawing off the conical tube disposed at one end of the stack or column. As will be understood, an individual tube to be separated may be nested so tightly with the next adjacent tube in the column, due to the conical configuration of the tubes and the nature of their interior and exterior surfaces, that separation may be rather difficult. Likewise, nested tubes may be situated relatively loosely with respect to one another in an overall stack or column, in which case separation is easy to accomplish. Thus, the force required for separation of individual tubes from a column or stack may vary widely and unpredictably.
On the other hand, the material and design of nested conical tubes must be taken into consideration as well in relation to the force to be exerted in separating individual tubes. For example, tubes having a relatively thin wall thickness, especially disposable plastic tubes, tend to deform very readily. Likewise, with tubes fabricated of cardboard, a risk exists that the surface may be damaged if excessive force is applied to such tubes during separation.
Devices for mechanically separating nested conical tubes are known. West German Offenlegungsschrift No. 21 31 957 describes a separating device wherein tubes are separated by grippers which are cooperatively controlled by a cam to exert a superimposed rotary and axial motion on the tubes.
Such device operates with a force which is predetermined for the tube separation operation. Therefore, a danger exists that tubes which are loosely nested may be damaged because the predetermined amount of force is greater than necessary to separate such tubes while other tubes which are tightly nested may fail to be separated because the predetermined amount of force is insufficient.